Meeting Abstract

P3.127  Wednesday, Jan. 6  The influence of acute and chronic stress on plasma glucose of a desert songbird DAVIES, S. **; SWEAZEA, K. L.; DEVICHE, P. ; Arizona State University, Tempe; Arizona State University, Tempe; Arizona State University, Tempe Scott.Davies@asu.edu

A regularly cited adaptive value of the avian stress response is the mobilization of energy stores to enable behavior aimed at increasing chances of survival. It is commonly accepted that this mobilized energy comes mainly in the form of glucose. However, the notion of acute stress-induced hyperglycemia is largely based on studies in captive rodents, with only a handful of studies on captive European Starlings and no data available on free-ranging birds. Furthermore, based on studies in chickens, chronically elevated corticosterone, the primary stress hormone in birds, is thought to elevate plasma glucose concentration by mobilizing endogenous glycogen stores and inhibiting glucose uptake by tissues. Yet little data is available on the affect of chronic stress on plasma glucose in wild birds. We investigated acute stress-induced changes in plasma glucose of free-ranging Abert’s Towhees, Pipilo aberti. In captivity, we then mimicked chronic stress conditions in these same birds by treating them with corticosterone-filled Silastic capsules. We predicted that acute stress would fail to elicit a hyperglycemic response but chronic corticosterone administration would increase plasma glucose. Consistent with studies of other captive birds, 60 minutes of handling and mild restraint failed to elicit a hyperglycemic response. Furthermore, corticosterone-treated towhees experienced a decrease in body weight, but plasma glucose in these birds did not differ from that of controls. These data suggest that the primary energy source mobilized to mount a stress response in birds may not be glucose.